106 lines
3.8 KiB
PHP
106 lines
3.8 KiB
PHP
<?php
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/*=======================================================================
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// File: JPGRAPH_MESHINTERPOLATE.INC.PHP
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// Description: Utility class to do mesh linear interpolation of a matrix
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// Created: 2009-03-09
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// Ver: $Id: jpgraph_meshinterpolate.inc.php 1709 2009-07-30 08:00:08Z ljp $
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//
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// Copyright (c) Aditus Consulting. All rights reserved.
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//========================================================================
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*/
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/**
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* Utility function to do linear mesh interpolation
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* @param $aDat Matrix to interpolate
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* @param $aFactor Interpolation factor
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*/
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function doMeshInterpolate( &$aData, $aFactor ) {
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$m = new MeshInterpolate();
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$aData = $m->Linear($aData,$aFactor);
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}
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/**
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* Utility class to interpolate a given data matrix
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*
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*/
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class MeshInterpolate {
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private $data = array();
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/**
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* Calculate the mid points of the given rectangle which has its top left
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* corner at $row,$col. The $aFactordecides how many spliots should be done.
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* i.e. how many more divisions should be done recursively
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*
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* @param $row Top left corner of square to work with
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* @param $col Top left corner of square to work with
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* $param $aFactor In how many subsquare should we split this square. A value of 1 indicates that no action
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*/
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function IntSquare( $aRow, $aCol, $aFactor ) {
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if ( $aFactor <= 1 )
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return;
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$step = pow( 2, $aFactor-1 );
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$v0 = $this->data[$aRow][$aCol];
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$v1 = $this->data[$aRow][$aCol + $step];
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$v2 = $this->data[$aRow + $step][$aCol];
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$v3 = $this->data[$aRow + $step][$aCol + $step];
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$this->data[$aRow][$aCol + $step / 2] = ( $v0 + $v1 ) / 2;
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$this->data[$aRow + $step / 2][$aCol] = ( $v0 + $v2 ) / 2;
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$this->data[$aRow + $step][$aCol + $step / 2] = ( $v2 + $v3 ) / 2;
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$this->data[$aRow + $step / 2][$aCol + $step] = ( $v1 + $v3 ) / 2;
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$this->data[$aRow + $step / 2][$aCol + $step / 2] = ( $v0 + $v1 + $v2 + $v3 ) / 4;
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$this->IntSquare( $aRow, $aCol, $aFactor-1 );
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$this->IntSquare( $aRow, $aCol + $step / 2, $aFactor-1 );
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$this->IntSquare( $aRow + $step / 2, $aCol, $aFactor-1 );
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$this->IntSquare( $aRow + $step / 2, $aCol + $step / 2, $aFactor-1 );
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}
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/**
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* Interpolate values in a matrice so that the total number of data points
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* in vert and horizontal axis are $aIntNbr more. For example $aIntNbr=2 will
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* make the data matrice have tiwce as many vertical and horizontal dta points.
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*
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* Note: This will blow up the matrcide in memory size in the order of $aInNbr^2
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*
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* @param $ &$aData The original data matricde
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* @param $aInNbr Interpolation factor
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* @return the interpolated matrice
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*/
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function Linear( &$aData, $aIntFactor ) {
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$step = pow( 2, $aIntFactor-1 );
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$orig_cols = count( $aData[0] );
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$orig_rows = count( $aData );
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// Number of new columns/rows
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// N = (a-1) * 2^(f-1) + 1
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$p = pow( 2, $aIntFactor-1 );
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$new_cols = $p * ( $orig_cols - 1 ) + 1;
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$new_rows = $p * ( $orig_rows - 1 ) + 1;
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$this->data = array_fill( 0, $new_rows, array_fill( 0, $new_cols, 0 ) );
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// Initialize the new matrix with the values that we know
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for ( $i = 0; $i < $new_rows; $i++ ) {
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for ( $j = 0; $j < $new_cols; $j++ ) {
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$v = 0 ;
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if ( ( $i % $step == 0 ) && ( $j % $step == 0 ) ) {
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$v = $aData[$i / $step][$j / $step];
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}
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$this->data[$i][$j] = $v;
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}
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}
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for ( $i = 0; $i < $new_rows-1; $i += $step ) {
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for ( $j = 0; $j < $new_cols-1; $j += $step ) {
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$this->IntSquare( $i, $j, $aIntFactor );
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}
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}
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return $this->data;
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}
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}
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?>
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